American realist painter Andrew Wyeth left an indelible impression on Eric Sambol after a museum class trip in the 1970s.

Many years later, the New Jersey businessman was able to acquire a work by Wyeth. It was the beginning of a collection that gradually expanded to include Wyeth’s equally famous father, the great classic novel illustrator N.C. Wyeth, and his son, Jamie Wyeth.

Sambol is parting with 13 of his Wyeths: six by Andrew, six by Jamie, and one by N.C. Christie’s auction house, which is selling the works Thursday, says it is one of the largest collections of Wyeths it has ever sold.

Sambol, a 53-year-old nature photographer and owner of a construction company in Toms River, N.J., said he fell in love with Andrew Wyeth’s work while on a high school trip to the Metropolitan Museum of Art in 1976 to see “Two Worlds of Andrew Wyeth: Kuerners and Olsons.”

“It solidified my fascination with the Wyeth family’s work, an enthrallment that remained with me for decades. ... No one could compare,” he said.

Sambol and his wife, Cynthia, a landscape designer, acquired their first Wyeth in 2000 with the purchase of “Flat Boat” by Andrew Wyeth. Later came N.C. Wyeth’s “Norry Seavey Hauling Lobster Traps Off Blubber Island” and Jamie Wyeth’s “Lighthouse Dandelions.”

All three works, which hung throughout the Sambols’ home, will be offered in this week’s auction.

“Flat Boat,” a 1988 watercolor of a winter scene showing a rowboat tied up near the shore by a bare tree, is estimated to sell for $250,000 to $350,000.

“Lighthouse Dandelions,” an oil painting of a luminous Maine lighthouse set against a dramatic night sky, has the same pre-sale estimate. “Norry Seavey,” a 1938 oil in hues of blue depicting a fisherman off the coast of Port Clyde, Maine, could fetch as much as $500,000.

Sambol said he met Andrew Wyeth and his frequent model, Helga Testorf, in 2004 at Wyeth’s home and studio in Chadds Ford, Pa. He also met Jamie, whose works includes landscapes, animal paintings and portraits of the Kennedy clan.